nonstandard (
http://definr.com/nonstandard)
adj 1: (linguistics) not conforming to the language usage of a
prestige group within a community; "a nonstandard
dialect is one used by uneducated speakers or socially
disfavored groups"; "the common core of nonstandard
words and phrases in folk speech"- A.R.Dunlap [ant:
standard]
2: varying from or not adhering to a standard; "nonstandard
windows"; "envelopes of nonstandard sizes"; "nonstandard
lengths of board" [ant:
standard]
3: not standard; not accepted as a model of excellence; "a
nonstandard text" [ant:
standard]